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UM2241
User manual
®
METERS AND MORE
compliant power line communication
system-on-chip
Introduction
This user manual, which targets application developers, provides complete information on how to use
the ST75MM in applications by describing the host interface, the available protocol services and the MIB
accessible through the host interface. For ordering information, mechanical and electrical device
characteristics, please refer to the ST75MM datasheet available at www.st.com.
August 2017
DocID030767 Rev 1
1/26
www.st.com
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Summary of Contents for ST METERS AND MORE UM2241
- Page 1 ST75MM in applications by describing the host interface, the available protocol services and the MIB accessible through the host interface. For ordering information, mechanical and electrical device characteristics, please refer to the ST75MM datasheet available at www.st.com. August 2017...
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Page 2: Table Of Contents
Contents UM2241 Contents Host interface .................. 6 Settings ..................... 6 Operations..................6 Acknowledge ..................7 Command frame format ..............7 Status message frame format (SM) ..........7 TREQ management ................9 Examples ..................9 Host interface commands ............. 14 Commands ..................14 Error codes.................. - Page 3 UM2241 Contents Configuring the ST75MM .............. 23 PHY configuration (MIB index 2) ............. 23 MAC configuration (MIB index 3) ............ 24 Manufacturer data (MIB index 6) ............. 24 Custom frequencies (MIB index 23) ..........24 Revision history ................25 DocID030767 Rev 1 3/26...
- Page 4 List of tables UM2241 List of tables Table 1: Command frame format ........................ 7 Table 2: Status message format ......................... 7 Table 3: Modem status format ........................8 Table 4: MIB status format .......................... 8 Table 5: Available commands ........................14 Table 6: List of error codes ........................
- Page 5 UM2241 List of figures List of figures Figure 1: Host controller to ST75MM connection scheme ................6 Figure 2: TREQ negotiation timing diagram ....................9 Figure 3: DL_DATA_SLAVE.indication transaction .................. 10 Figure 4: DL_DATA_SLAVE.indication transaction in case of no ack ............11 Figure 5: MIB_Write.request transaction ....................
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Page 6: Host Interface
Host interface UM2241 Host interface Settings The host interface is used to interface the ST75MM to the host controller, it allows exchanging data, configuration and control messages. The host interface can be managed by the host controller with a half-duplex asynchronous serial port (UART) plus an additional synchronization signal which will be referenced, in this document as TREQ. -
Page 7: Acknowledge
UM2241 Host interface Section 1.7: "Examples" contains some examples on how complex operations shall be managed between the host controller and the ST75MM. Acknowledge In order to improve the serial link robustness, every frame except the SM must be acknowledged by the receiver within a given period T (host interface timings are managed through a dedicated MIB object, see Section 3.1: "MIB objects"... -
Page 8: Table 3: Modem Status Format
Host interface UM2241 Starting Field Size Value Description Byte SM start 0x3F Used to mark the start of the SM Modem Bit mask showing the status of the ST75MM modem status Bit mask showing which MIB objects have been MIB status reconfigured by the host controller The following table shows the modem status field possible values. -
Page 9: Treq Management
UM2241 Host interface Name MIB index Description Manufacturer data Physical address (ACA) of the modem and serial number Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved TREQ management Here below a timing diagram of the priority negotiation of the serial link is depicted, first of all the host controller wanting to send a command to the ST75MM drives low the TREQ line, waiting for the SM frame before sending the message. -
Page 10: Figure 3: Dl_Data_Slave.indication Transaction
Host interface UM2241 Figure 3: DL_DATA_SLAVE.indication transaction The same transaction, in case the acknowledge (the same applies in case the –indication is lost) is lost, is the one depicted in the next figure, where the second DL_DATA_SLAVE.indication message frame uses 0x03 as start of the frame byte instead 0x02 as the first one, to let the host controller check if the message has already been received or not. -
Page 11: Figure 4: Dl_Data_Slave.indication Transaction In Case Of No Ack
UM2241 Host interface Figure 4: DL_DATA_SLAVE.indication transaction in case of no ack This is an example of the MIB_Write request coming from the host controller, as the initiator is the host controller, the session is started with the negotiation with the ST75MM to gain priority on the serial link DocID030767 Rev 1 11/26... -
Page 12: Figure 5: Mib_Write.request Transaction
Host interface UM2241 Figure 5: MIB_Write.request transaction The MIB_Read request coming from the host controller follows the same mechanism as the MIB_Write. 12/26 DocID030767 Rev 1... -
Page 13: Figure 6: Mib_Read.request Transaction
UM2241 Host interface Figure 6: MIB_Read.request transaction DocID030767 Rev 1 13/26... -
Page 14: Host Interface Commands
Host interface commands UM2241 Host interface commands Commands The following table is a summary of the available commands, each command will be better specified later on. Table 5: Available commands .confirm .confirm Command .request .indication Description (positive) (negative) Modifies the value of a specific MIB object (.request) or notifies MIB_Write... -
Page 15: Mib_Write
UM2241 Host interface commands MIB_Write This command is initiated by the host controller to request a modification on a specific MIB object, the MIB object index and the expected new value are embedded in the payload of the .request message, while the .confirm messages carry the information about the success of the operation. -
Page 16: Mib_Read Request
Host interface commands UM2241 2.4.1 MIB_Read request Issued by: host controller Command code: 0x0C Payload size: 1 byte Payload content: MIB object index (1 byte) 2.4.2 MIB_Read positive confirm Issued by: ST75MM Command code: 0x0D Payload size: variable Payload content: ... -
Page 17: Bio_Reset Negative Confirm
UM2241 Host interface commands 2.5.3 BIO_Reset negative confirm Issued by: ST75MM Command code: 0x3F Payload size: 1 byte Payload content: Error code (1 byte) 2.5.4 BIO_Reset indication Issued by: ST75MM Command code: 0x3E Payload size: 1 byte Payload content: ... -
Page 18: Hi_Ping
Host interface commands UM2241 Applicative payload (variable) Only commands having the protocol type equal to 0 shall be processed, if a command with a different protocol type is received it shall be discarded and no action performed. HI_Ping HI_Ping commands can be used to periodically test the serial link between the host controller and the ST75MM modem, and the healthy state of the modem itself. -
Page 19: Management Information Base (Mib)
UM2241 Management information base (MIB) Management information base (MIB) MIB objects The following table shows the MIB objects present in the ST75MM modem, reserved MIB objects should not be modified and notifications involving those MIB objects can be ignored. Table 8: MIB objects list Index Name Size... -
Page 20: Table 11: Mac Configuration Mib Object (3)
Management information base (MIB) UM2241 Byte Field Sub-field Description and values 0: next transmitted frame will start immediately Zero crossing 1: next transmitted frame will start at the next zero crossing event 0: single channel operations RX channel 1: dual channel operations 0: transmit on high channel TX channel 1: transmit on low channel... -
Page 21: Table 12: Manufacturer Data Mib Object (6)
UM2241 Management information base (MIB) Table 12: Manufacturer data MIB object (6) Byte Field Sub-field Description and values 0-15 Device ID Device identification string 16-21 Physical address of the node (ACA) Table 13: Host interface timings MIB object (14) Sub- Byte Field Description and values... - Page 22 Management information base (MIB) UM2241 Byte Field Sub-field Description and values Discarded Counter of frames discarded from the MAC layer due to frames busy upper layers condition Overcurrent Number of overcurrent events in the last transmitted events frame 22/26 DocID030767 Rev 1...
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Page 23: Configuring The St75Mm
UM2241 Configuring the ST75MM Configuring the ST75MM Only the four MIB objects detailed below need to be programmed/monitored to ensure correct operation as receiver-only in the CENELEC 132.5 kHz band. PHY configuration (MIB index 2) In order to configure the ST75MM modem to work as a single channel receiver in the CENELEC 132.5 kHz band the MIB object 2 shall be programmed with the following string: {0x31, 0x95, 0x0A, 0x3B, 0x58, 0x9B} Corresponding to the following configuration (selected values are in bold). -
Page 24: Mac Configuration (Mib Index 3)
Configuring the ST75MM UM2241 Byte Field Sub-field Description and values Receiving mode for higher channel RX high 0: FSK modulation channel 1: any PSK modulation Reserved Reserved Reserved {0x3B, 0x58, 0x9B} MAC configuration (MIB index 3) In order to configure the ST75MM modem to work in the normal MAC mode the MIB object 3 shall be programmed with the following string: {0x01, 0x00} Corresponding to the following configuration (selected values are in bold). -
Page 25: Revision History
UM2241 Revision history Revision history Table 19: Document revision history Date Revision Changes 09-Aug-2017 Initial release. DocID030767 Rev 1 25/26... - Page 26 ST products and/or to this document at any time without notice. Purchasers should obtain the latest relevant information on ST products before placing orders. ST products are sold pursuant to ST’s terms and conditions of sale in place at the time of order acknowledgement.
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